Re: [RFC] "biological parent" pid

[Michael Buesch <mbuesch@freenet.de>]

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Quoting Tim Schmielau <tim@physik3.uni-rostock.de>:
> The ppid of a process is not really helpful if I want to reconstruct the 
> real history of processes on a machine, since it may become 1 when the
> parent dies and the process is reparented to init.
> 
> I am not aware of concepts in Linux or other unices that apply to this
> case. So I made up the "biological parent pid" bioppid (in contrast to the
> adoptive parents pid) that just never changes.
> Any user of it must of course remember that it doesn't need to be a valid 
> pid anymore or might even belong to a different process that was forked in 
> the meantime. bioppid only had to be a valid pid at time btime (it's
> a (btime, pid) pair that unambiguously identifies a process).
> 
> Comments? (other that I just broke /proc/nnn/status parsing once again :-)

Eh, I can't see how this bioppid would be useful.
Help me. Examples?

> Tim
> 
> 
> --- linux-2.6.10/include/linux/sched.h	2004-12-24 22:33:59.000000000 +0100
> +++ linux-2.6.10-ppid/include/linux/sched.h	2005-01-31 19:20:00.000000000 +0100
> @@ -556,6 +556,7 @@ struct task_struct {
>  	unsigned did_exec:1;
>  	pid_t pid;
>  	pid_t tgid;
> +	pid_t bioppid;                  /* biological parents */
>  	/* 
>  	 * pointers to (original) parent process, youngest child, younger sibling,
>  	 * older sibling, respectively.  (p->father can be replaced with 
> 
> --- linux-2.6.10/kernel/fork.c	2004-12-24 22:33:59.000000000 +0100
> +++ linux-2.6.10-ppid/kernel/fork.c	2005-01-31 18:15:39.000000000 +0100
> @@ -889,6 +889,7 @@ static task_t *copy_process(unsigned lon
>  	p->tgid = p->pid;
>  	if (clone_flags & CLONE_THREAD)
>  		p->tgid = current->tgid;
> +	p->bioppid = current->pid;
>  
>  	if ((retval = security_task_alloc(p)))
>  		goto bad_fork_cleanup_policy;
> 
> --- linux-2.6.10/fs/proc/array.c	2004-12-24 22:35:00.000000000 +0100
> +++ linux-2.6.10-ppid/fs/proc/array.c	2005-01-31 18:19:02.000000000 +0100
> @@ -165,6 +165,7 @@ static inline char * task_state(struct t
>  		"Tgid:\t%d\n"
>  		"Pid:\t%d\n"
>  		"PPid:\t%d\n"
> +		"BioPPid:\t%d\n"
>  		"TracerPid:\t%d\n"
>  		"Uid:\t%d\t%d\t%d\t%d\n"
>  		"Gid:\t%d\t%d\t%d\t%d\n",
> @@ -172,6 +173,7 @@ static inline char * task_state(struct t
>  		(p->sleep_avg/1024)*100/(1020000000/1024),
>  	       	p->tgid,
>  		p->pid, pid_alive(p) ? p->group_leader->real_parent->tgid : 0,
> +		p->bioppid,
>  		pid_alive(p) && p->ptrace ? p->parent->pid : 0,
>  		p->uid, p->euid, p->suid, p->fsuid,
>  		p->gid, p->egid, p->sgid, p->fsgid);
> 
> --- linux-2.6.10/kernel/acct.c	2004-12-24 22:34:58.000000000 +0100
> +++ linux-2.6.10-ppid/kernel/acct.c	2005-01-31 18:19:35.000000000 +0100
> @@ -446,7 +446,7 @@ static void do_acct_process(long exitcod
>  #endif
>  #if ACCT_VERSION==3
>  	ac.ac_pid = current->tgid;
> -	ac.ac_ppid = current->parent->tgid;
> +	ac.ac_ppid = current->bioppid;
>  #endif
>  
>  	read_lock(&tasklist_lock);	/* pin current->signal */
> -
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> 

-- 
Regards Michael Buesch  [ http://www.tuxsoft.de.vu ]



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